This invention relates to a method of, and to apparatus for, cutting a block of material such as clay, particularly cutting a clay batch into brick mouldings.
In this regard, reference is made to another copending application Ser. No. 942,034 filed on Sept. 13, 1978, as well as earlier, commonly assigned U.S. Pat. Nos. 3,602,963, 3,976,417 and 4,085,635. Additionally, other known devices for cutting clay columns include the following U.S. Pat. Nos. 1,275,775, 2,099,119, 3,461,196, 3,492,703, 3,805,655 and 3,838,621.
These devices include those where clay columns are pushed through a cutting frame at right angles to the primary feed direction, as in U.S. Pat. Nos. 3,461,196 and 3,602,963. Traditionally the columns are pushed quite hard and there are many types of bricks where such hard pushing is undesirable since either the column, the resulting cut members or both would be damaged. Another push type is shown in U.S. Pat. No. 3,805,655.
Cutting wires have also been placed in rotating frames as in U.S. Pat. No. 1,275,775 for cutting file which is supported on a conveyor belt or have been part of a punching tool as in U.S. Pat. No. 3,976,417.
Cutting clay columns with a cutting device by means of a cutting frame, supported so that it can rotate, in which cutting wires are located at intervals from each other is also known and reference is made to U.S. Pat. No. 3,838,621. The column is conveyed on a transportation device comprised of a number of arrow conveyor belts located close to each other, and the cutting wires sink into holes defined between the belts after every cut.
The disadvantage of this apparatus is that a separate belt table or assembly line must be available for each cut length so that changing cutting lengths is a very time-consuming and expensive operation. Another disadvantage is that the clay columns are not completely supported during cutting, so that the lower edges of bricks can be deformed when being cut. Further, the wires can only be cleaned after every cut by a relatively time-and-energy-consuming device, and since the cleaning device has to be moved along the wires while they are held in a stationary position an additional time delay factor is created. A similar device is disclosed in U.S. Pat. No. 4,085,635, and an improved system is disclosed in the copending application Ser. No. 924,034. U.S. Pat. No. 2,099,119 discloses a device for cutting yeast that operates through slots in a manner somewhat similar to those that operate within slots that extend transversely across the path of the yeast. Finally, U.S. Pat. No. 3,492,703 discloses a vertical cutter for concrete that moves up and down in a sawing fashion. It does not move through the work in a single pass and would not produce cuts that would be free of marks.
German patent specification No. 2,453,934 discloses a method and apparatus for cutting brick mouldings from a clay strand in which elongate clay batches are passed to a cutting frame provided with cutting wires. The cutting frame is pivotably supported at one side so as to be pivotable about a shaft disposed below the path of the batch. In use, the cutting frame is pivoted upwardly during forward feed of the batch, which forward feed is effected by means of a pusher, at a speed adapted to the feed of the batch so that the exit of the cutting wires from the surface of the batch remains at the same place and that part of the cutting wires within the batch moves longitudinally of the batch. Forward feed of the batch is then stopped and the cutting frame is pivoted downwardly to return to the starting position thereof so that the wires complete the cut through the batch and penetrate into the succeeding batch.
The disadvantage of this apparatus is that, because the batches are cut in two intermittent strokes and the wires remain in the batch between the strokes, a clearly visible mark occurs at the cutting surfaces and edges of the brick after the end of the forward feed due to the relaxation of the wires and of the batches.
Another disadvantage of that apparatus is that, due to the wide angle required between the wires and the batch support surface at the beginning of the cut, the batch which is to be cut must be supported against the succeeding batch to prevent displacement. The quality of such a support depends on the shape and weight of the batch so that, more particularly when cutting lightweight material, such as hollow bricks, the cutting quality varies from cutting phase to cutting phase due to the varying cutting pressure against the direction of feed.
German patent specification No. 2,511,158 discloses an apparatus similar to that disclosed in German patent specification No. 2,453,934 but differing therefrom in that the cutting frame is pivoted about a shaft above the path of the batch and by virtue of the fact that no pusher is used to feed the batch.
The apparatus of German patent specification No. 2,511,158 is detrimental for the same reasons as those previously described in connection with German patent specification No. 2,453,934. The most serious problem, however, is that the cutting surfaces and edges of the mouldings become marked by the wires which remain within the batch between cuts.